Thornless Barberry Shrubs

Plant year round in USDA zones 7 through 8.

The thornless barberry shrub (Berberis thunbergii "Thornless") is an anomaly among the barberry varieties. While most have thorns, the thornless barberry is essentially barbless. Its bright green summer foliage changes to a dramatic red-orange in the fall. Like its family members, it is complete with red berries -- a delight to birds that love a special treat. The thornless Japanese barberry shrub fares best in U.S. Department of Agricultural plant hardiness zones 4 through 8.

Characteristics

The thornless Japanese barberry is a deciduous ground cover and shrub. It grows to a height of 3 to 4 feet and spreads 3 to 5 feet. Growth rate is slow to moderate. Its form is globelike, compact and rounded -- more rounded and compact than other barberry varieties. Flowers are yellow and bloom in the spring. Fall leaves change from green to reddish and even yellow, making it a nice accent shrub for the landscape.

Uses

The thornless barberry is an excellent choice for a low hedge or border because of its denseness. It works well for erosion control, and, because it has a 5-foot spread, it makes a nice ground cover. As an accent plant, it’s stunning in rock gardens. It also works well in mass plantings and groupings. Because it is widely adaptable, it can tolerate most soil and water conditions. However, it does best in full sun.

Planting

The thornless barberry does well in sandy, clay and loamy soils with a soil pH that is acidic, neutral, alkaline or slightly alkaline. Though it grows best in full sun, it can do well in partial shade. Norman Winter, Mississippi State University horticulturist, recommends preparing the soil with a mix of 3 to 4 inches of organic matter and 5-10-5 fertilizer before planting barberry. Consider the spread when planting the shrub. Plant the shrubs closer for a hedge.

Disease and Pests

Disease and insects are usually not a serious concern with barberry. However, anthracnose is a fungal disease that shows up as round, brown spots on the upper leaf surface. Powdery mildew causes a white coating on the leaves, and phyllosticta leaf spot causes purple spots on the leaves. Sulfur-based fungicides treat fungi, including powdery mildew. Aphids create a sticky substance on the leaves. Songbirds devour aphids, but you can also get aphid traps. Scale insects can be controlled with horticultural oil. The barberry webworm is a small caterpillar with white spots that devours leaves. Spray with a product containing bacillus thuriengensis (BT).